Pollen Linked to Coronavirus Spread in Nasal Cells: EAACI 2026
Pollen exposure may increase the spread of coronavirus infections within the nasal lining by weakening antiviral immune responses and promoting viral transmission between cells. Research presented at the 2026 annual congress of the European Academy of Allergy and Clinical Immunology indicates that exposure to birch and timothy grass pollen aerosols significantly boosts the production of infectious viral particles for both human coronavirus 229E (hCoV-229E) and SARS-CoV-2.
How Pollen Impacts Viral Infection
Researchers investigating the mechanisms behind this increased susceptibility used a near-physiological model of differentiated human nasal epithelial cells. According to the study, pollen exposure induced marked mucus production and altered ciliary activity in these cells for up to 72 hours. These physiological changes were accompanied by a decrease in antiviral mediators, specifically IL-29 and IFN-β, alongside an increase in pro-inflammatory cytokines such as IL-6 and thymic stromal lymphopoietin (TSLP).
Did You Know? Exposure to pollen aerosols causes ciliary activity and mucus production in nasal cells that can persist for up to 72 hours, potentially creating an environment more conducive to viral replication.
Mechanisms of Viral Spread
Molecular analysis suggests that pollen alters how the virus distributes throughout nasal tissue. While virus-only control cultures showed high levels of viral gene expression concentrated within a small number of ciliated cells, pollen-exposed cultures exhibited a much broader distribution of the virus across the tissue. Proteomic profiling revealed that this shift is linked to changes in pathways associated with apoptosis, cellular stress, and cAMP- and MAPK-mediated signalling.
Expert Insight: Samantha Carter notes that these findings suggest a significant interaction between environmental allergens and respiratory viruses. By suppressing the body’s early antiviral defenses while simultaneously triggering inflammatory pathways, pollen may fundamentally change the landscape of the nasal epithelium, making it easier for viruses to move from cell to cell.
What May Happen Next
These findings could lead to a reassessment of how seasonal allergy management intersects with respiratory virus prevention. If pollen-induced inflammation facilitates broader viral distribution, health experts may investigate whether mitigating allergic responses during peak pollen seasons could serve as a strategy to reduce the severity or spread of respiratory infections. Future research may focus on whether clinical interventions aimed at these specific inflammatory pathways could limit the cell-to-cell transmission of coronaviruses in allergic individuals.
Frequently Asked Questions
Which viruses were studied in relation to pollen exposure?
The research examined the impact of birch and timothy grass pollen aerosols on human coronavirus 229E (hCoV-229E) and SARS-CoV-2.
How does pollen affect the immune response in the nose?
According to the study, pollen exposure reduces the levels of antiviral mediators IL-29 and IFN-β while increasing pro-inflammatory cytokines like IL-6 and TSLP, effectively impairing the epithelial antiviral response.
Does pollen change how the virus spreads within the nose?
Yes. While the virus is typically confined to a small number of ciliated cells, pollen exposure appears to facilitate a much broader distribution of the infection throughout the nasal tissue.
How do you adjust your personal health precautions during high-pollen seasons to account for potential respiratory risks?